1. Field of the Invention
The present invention relates to piezoelectric components such as a surface acoustic wave (SAW) device used in a SAW duplexer or SAW filter, or a piezoelectric thin film filter, that are used for example in mobile communication equipment such as mobile telephones, and a manufacturing method thereof, and relates, in particular, to a chip-size packaged piezoelectric component in which a piezoelectric element is flip-chip mounted on a wafer (piezoelectric substrate) at the wafer level, and a manufacturing method thereof.
2. Description of Related Art
In a piezoelectric component (SAW device) to be installed in a mobile phone or the like, a predetermined hollow section around the comb-shaped electrodes (IDT electrodes) thereof is required.
Conventionally, to reduce the size of a SAW device, a SAW element chip is flip-chip bonded (face-down bonded) to a wired substrate using gold (Au) bumps or solder bumps, and the entire SAW element chip is subjected to resin encapsulation by resin or the like to configure a small package size SAW device (refer to Japanese Unexamined Patent Publication No. 2004-147220).
In addition, to reduce the size and height of a SAW device, a microminiaturized chip size packaged SAW device is proposed in which a predetermined hollow section is formed around a comb-shaped electrode section (IDT electrode section), and while maintaining this hollow section, the entire integrated piezoelectric substrate (wafer) on the comb-shaped electrode side, is sealed by resin, external connection electrodes are formed, and then the wafer is divided into individual SAW devices by dicing along predetermined markings (refer to Japanese Unexamined Patent Publication No. 2006-246112).
However, with the piezoelectric components and manufacturing methods thereof described in the related art above, piezoelectric elements are formed upon a two-dimensional flat surface (principal surface) of the piezoelectric substrate. Therefore, because when the size of the piezoelectric component (SAW device) is reduced, with this reduction in size the active face (functional surface) of the piezoelectric element is also reduced in size, maintaining a desired level of performance while reducing size is extremely difficult.
Furthermore, in methods of manufacturing piezoelectric components by simply affixing piezoelectric substrates (wafers) to one another, through electrodes must be formed. However this requires the formation of through holes (via holes), and other steps including a plating step for filling the through holes to form the through electrodes, or a step for plugging the through holes. Furthermore, if the respective piezoelectric substrates are made of different materials, problems can occur such as the overall piezoelectric substrate undergoing “warping”.